UFO Glossary
Essential terms and concepts in ufology, UAP research, and extraterrestrial studies. Click any term to read the full definition.
UFO (Unidentified Flying Object)
A UFO is any airborne object or phenomenon that cannot be immediately identified by the observer. The term was coined by the US Air Force in 1953 to replace the earlier phrase 'flying saucer.' While most UFO sightings are eventually explained as aircraft, satellites, or weather phenomena, a small percentage remain unexplained.
UAP (Unidentified Aerial Phenomena)
UAP is the term now preferred by the US Department of Defense, NASA, and many governments over 'UFO.' It was adopted to remove the stigma associated with the older term and to broaden the scope beyond physical objects to include unexplained aerial phenomena such as lights and radar anomalies. The Pentagon's UAP Task Force was established in 2020.
Close Encounter
A classification system created by astronomer J. Allen Hynek in 1972 to categorize UFO sightings by proximity. Close Encounters of the First Kind involve visual sighting within 150 meters, the Second Kind include physical evidence, and the Third Kind involve contact with occupants. Steven Spielberg later popularized the term with his 1977 film.
NUFORC (National UFO Reporting Center)
NUFORC is a US-based organization that collects and catalogues UFO sighting reports from the public. Founded in 1974 by Robert Gribble, it maintains one of the largest databases of UFO reports in the world with over 170,000 entries. Reports are submitted via phone hotline or web form and are reviewed before publication.
MUFON (Mutual UFO Network)
MUFON is the world's oldest and largest civilian UFO investigation organization, founded in 1969. It operates a global network of trained field investigators who examine reported sightings using standardized protocols. MUFON maintains a comprehensive case management system and publishes the monthly MUFON UFO Journal.
Project Blue Book
Project Blue Book was the US Air Force's official investigation into UFOs, running from 1952 to 1969. It catalogued 12,618 sightings and concluded that most could be explained by natural phenomena or conventional aircraft. However, 701 cases (5.5%) were classified as 'unidentified.' The project was shut down after the Condon Report recommended no further study.
Roswell Incident
The Roswell Incident refers to the crash of an unknown object near Roswell, New Mexico in July 1947. The US military initially announced recovery of a 'flying disc' before retracting the statement and claiming it was a weather balloon. Decades later, the Air Force attributed the debris to Project Mogul, a classified surveillance balloon program. It remains the most iconic UFO event in history.
Area 51
Area 51 is a highly classified US Air Force facility located within the Nevada Test and Training Range. The US government did not officially acknowledge its existence until 2013 through declassified CIA documents. While the base is used for testing experimental aircraft like the U-2 and SR-71, it has become the most famous location in UFO lore, with many believing it houses recovered alien technology.
Tic Tac UFO
The Tic Tac UFO refers to a white, capsule-shaped object encountered by US Navy pilots from the USS Nimitz carrier group off the coast of San Diego in November 2004. Commander David Fravor reported the object performed extraordinary aerial maneuvers including instantaneous acceleration. The Pentagon officially released the FLIR1 infrared video in 2020, making it one of the most credible military UFO encounters on record.
Foo Fighter
Foo fighters were mysterious aerial phenomena reported by Allied aircraft pilots during World War II, particularly over Europe and the Pacific. Pilots described them as glowing orbs or balls of fire that followed their aircraft but never attacked. The term was coined by the 415th Night Fighter Squadron. No conclusive explanation has ever been established, though theories range from St. Elmo's fire to enemy secret weapons.
Men in Black
Men in Black (MIB) are figures from UFO folklore said to visit UFO witnesses and researchers to intimidate them into silence. They are typically described as men in dark suits with unusual physical features and robotic behavior. Reports date back to the 1950s, with Albert Bender's 1953 account being among the earliest. The concept was later adapted into the popular film franchise.
Crop Circle
Crop circles are geometric patterns created by flattening crops in agricultural fields. While many have been proven to be human-made art, some enthusiasts believe certain formations are too complex or appear too quickly to be man-made. The phenomenon gained worldwide attention in the 1970s and 1980s, particularly in southern England. Some ufologists associate them with alien communication attempts.
Alien Abduction
Alien abduction refers to claims by individuals who say they were taken against their will by extraterrestrial beings. Common reported elements include medical examinations, telepathic communication, and missing time. The phenomenon entered public consciousness with the 1961 Betty and Barney Hill case. Skeptics attribute these experiences to sleep paralysis, false memories, or psychological factors.
SETI (Search for Extraterrestrial Intelligence)
SETI is the collective term for scientific efforts to detect signs of intelligent life beyond Earth, primarily by scanning the sky for radio signals. The SETI Institute, founded in 1984, is the leading organization in this field. Projects like SETI@home have allowed millions of volunteers to contribute computing power to analyze radio telescope data for potential alien signals.
Fermi Paradox
The Fermi Paradox is the contradiction between the high probability of extraterrestrial civilizations existing in the universe and the lack of evidence for, or contact with, such civilizations. Named after physicist Enrico Fermi, who reportedly asked 'Where is everybody?' during a 1950 lunch conversation. Proposed solutions range from the Great Filter hypothesis to the Zoo hypothesis, where advanced aliens deliberately avoid contact.